Electroplating upon a metallized surface



Oct. 22, 1935. A. G. RUSSELL 2,018,471

ELECTROPLATING UPoNA METALLIZED SURFACE Filed June 20, 1954 /N VE N TOR A. G. RUSSELL BV MMA/Q A 7' TOP/VE)l Patented Oct. 22, 1935 ELECTROPLATING UPON A METALLIZED SURFACE Alexander G. Russell, Red Bank, N. J., assigner to Bell Telephone Laboratories, Incorporated, v New York, N. Y., a corporation. of New York Application June 20, 1934, Serial No. 731,424

2 Claims.

This invention relates to the art of electrodeposition and particularly to the art of depositing a metal upon a metallized non-conducting surface.

For the purpose of illustration this invention 5 will be described as applied to the art of electrodepositing a nickel master upon a metallized wax original of a. phonograph recording.

It has been observed that when it is attempted to electrodeposit nickel directly upon the surface .lil of a wax master record which has been rendered conductive by a suitable coating such, for example, as sputtered gold or silver, the edges of the nickel deposit tend to curl away from the surface during the early stages of the deposition and this 13 curl becomes permanent as the thickness of the coating increases. If the curl extends across a portion of the recorded matter the entire master is rendered worthless.

The direct cause of the curl appears to be a tension in the thin deposit of nickel which pulls it away from the wax surface and with it the sputtered metal or other conductive coating. The proximate cause of the curl may be various impurities which appear in the average commercial nickel-plating bath and the removal of which requires unusual care and attention.

The object of this invention is an improved article upon which nickel metal can be deposited directly Without unusual care and unaccompanied by curling.

In general, this invention consists in securing metal to the edges of the non-conducting material and in contact with the bath so that as the deposit forms, it forms also upon the metal, to which it readily adheres. Since the metal is iirmly secured to the edges of the non-conducting material the deposit will exhibit no tendency to curl. The metal may be trimmed oi when the electroplate is nished.

The invention may best be described with reference to the accompanying drawing in which Fig. 1 is a plan view of a Wax master record ready for plating;

Fig. 2 is an elevation in section of a portion of a master record plated with nickel in the usual manner; Y

Fig. 3 is an elevation in section of a portion of a master record made and plated with nickel in accordance with this invention; and

Fig. 4 is an elevation in section of a portion of a master record made and plated with nickel in accordance with a modification of this invention.

The wax master chosen to illustrate this invention is of a composite type comprising a recessed metal disc on which is melted a thin layer of wax.

The invention, however, is not limited to this form of disc and can be applied not only to `any form of Wax recording but to insulators generally, which are to be plated .directly with a nickel metal. p

Referring now to Fig. 1, I0 is a wax surface of a master record which is to be plated, I I. is a portion of a rubber shield used to limit the `surface to be plated and I2 is the upturned edge of the remainder of the shield which covers the back of the record.

In the elevation of Fig. 2, the wax surface I0 is seen supported by a recessed metal disc I3 and plated with a substantial deposit of nickel I4 in the usual manner. The wax surface is coated, for example, by the sputtering process by which a thin layer of metal, probably oi the order of a millionth of an inch in thickness, is deposited on the wax surface to render it electro-conductive. Such a deposit has practically no resistance to 2J bending and consequently, when the nickel deposited thereon begins to curl, the deposit is drawn away from the wax surface. Such a curl is shown at I5 in Fig. 2. The curl usually extends inward across several of the grooves containing recorded matter, and consequently the nickel master so formed is not a true negative of the Wax and is worthless.

In order to prevent the curl from forming, or at least, to prevent it from extending over the grooved portion of the disc, some metal must be provided for the deposit to adhere to, and the metal must be capable of resisting the bending stresses induced therein by the nickel as it is deposited. This metal can be supplied in the form of spring clips I6 as shown in Fig. 3. The clips may be U-shaped, phosphor-bronze wire slipped over theI edge of the Wax master record and adapted to contact the electro-conductive coating on the wax surface over a portion of the uncut margin I1. The end I8 of each clip may be bent upward slightly to avoid tearing out portions of the Wax as the clip is placed on the disc and to insure a sliding contact between the clip and electro-conducting coating. The clips may be spaced equidistantly around the periphery of disc I1 and preferably not more than two inches apart.

The metal can also take the form of a ring I9 (Fig. 4) embedded in the wax I0 near the periphery thereof and extending inward beyond the edge of rubber shield I I; or instead of a ring, the metal can be supplied as small arcs spaced equidistantly about the edge of the disc asin the case of the clips. The ring or arcs need not be embedded in the wax, but may be merely laid thereon and held 55 in place by shield I I. Numerous other forms may suggest themselves to those skilled in the art, the only limitations to be considered being the resistance to bending required of the metal, and the proper .spacing of the discontinuous forms about the edge of the record. It is desirab1e,`how ever, to have the metal and disc, or other material* to be plated, united to form a 'single unit for ease of handling.

After the clips or the equivalent are properly located on the wax master record, shields II and I 2 are placed over the portions of disc I3 which are not to be plated and the whole is placed in an ordinary nickel-plating bath with adequate means provided therein for agitating the bath to obtain a uniform deposit on the record. After the required thickness oi nickel is deposited, the record is taken from the bath and shields II and I2 are removed from the record. The deposit will be found to be substantially flat over the entire periphery of the disc and adhering iirmly to the clips. To separate the deposit from the wax, clips I6 may be bent at III to permit the deposit to be lifted vertically from disc I3 and such wax as may come oir with the deposit is removed either by melting or with the aid oi a solvent, or by a combination of both means. The deposit is then center-drilled, placed in a trimming machine and the edge, with clips I8 adhering thereto, cut oif at some point X (Fig. 3) leaving a perfectly fiat nickel master suitable for further processingv or for use as a die in a press to form reproducible records. p

Although this invention has been described with reference to a phonograph record, it is not limited in its application thereto, but it may be used genl0 erally whenever it is desired to deposit nickel by ordinary means upon an insulator rendered conductive by a thin layer of electro-conductive ma terial.

What is claimed is:

1. As an article of manufacture, a wax master record with a metal coated surface and clips secured to the metal coated surface and spaced about the periphery of the record.

2. As an-article of manufacture, a record with 20 a metal coated surface and U-shaped clips frictionally engaging the surface and uniformly spaced about the periphery of the record to prevent a subsequent electroplate from curling away from the coated surface.

l ALEXANDER G. RUSSELL. 

